Keithley 2700, User Manual, Page: 160 / 500

Model 2700 Multimeter/Switch System User’s Manual Range, Digits, Rate, Bandwidth, and Filter 4-9
The front panel RATE settings for all but the AC functions are explained as follow:
• FAST sets integration time to 0.1 PLC. Use FAST if speed is of primary
importance (at the expense of increased reading noise and fewer usable digits).
• MEDium sets integration time to 1 PLC. Use MEDium when a compromise
between noise performance and speed is acceptable.
• SLOW sets integration time to 5 PLC. SLOW provides better noise performance at
the expense of speed.
For the AC functions (ACV, ACV dB, and ACI), the RATE key sets integration time and
bandwidth. As listed in
Table 4-4 , FAST sets NPLC to 1, while the MEDium and SLOW
NPLC settings are ignored (see “Bandwidth,” page 4-10 , for details).
From the front panel, setting the rate for one function affects all the other functions. For
example, if you set DCV for medium speed, the other functions will also set to medium
speed. For remote programming, each function can have its own unique rate setting
(0.01 to 50 or 60 PLC).
NOTE
Rate cannot be set for continuity. It is fixed at 0.01 PLC.
Setting measurement speed
— The RATE key is used to set measurement speed from the
front panel. Simply press RATE until the desired speed annunciator (FAST, MED, or
SLOW) turns on.
NOTE
The Model 2700 uses internal references to calculate an accurate and stable
reading. When the NPLC setting is changed, each reference must be updated to
the new NPLC setting before a reading is generated. Therefore, frequent NPLC
setting changes can result in slower measurement speed.
Table 4-4
Rate and bandwidth settings
Function
Rate and bandwidth
Fast Medium Slow
DCV, DCI
ACV, ACI
Ω
2,
Ω
4
FREQ, PERIOD
Continuity
NPLC=0.1
NPLC=1, BW=300
NPLC=0.1
APER=0.01s
NPLC=0.01 NPLC=1
NPLC=X, BW=30
NPLC=1
APER=0.1s
N/A NPLC=5
NPLC=X, BW=3
NPLC=5
APER=1s
N/A
Notes: NPLC = number of power line cycles.
BW = lower limit of bandwidth (in Hz).
APER = aperture in seconds.
N/A = not available.
X = setting ignored.